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@moss-dev/moss-web / MossClient

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MossClient

MossClient is the entry point for the Moss Browser/WASM SDK. It manages indexes and documents and runs semantic search locally in the browser. Once an index is loaded with loadIndex, queries run entirely in-browser with no server round-trips. This is the in-browser client. For server-side (Node.js) code, use the Node MossClient instead. See Browser vs Node for guidance. This client does not have sessions.

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Example

import { MossClient } from "@moss-dev/moss-web";

const client = new MossClient("your-project-id", "your-project-key");

// Create an index with documents
await client.createIndex("docs", [
  { id: "1", text: "Machine learning fundamentals" },
  { id: "2", text: "Deep learning neural networks" },
]);

// Load the index into the browser, then query it
await client.loadIndex("docs");
const results = await client.query("docs", "AI and neural networks");

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Creating a client

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Constructor (lazy)

new MossClient(projectId, projectKey, options?): MossClient
Creates a client with lazy initialization. The WebAssembly module and embedding model load on the first API call.

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Parameters

ParameterTypeDescription
projectIdstringYour project identifier.
projectKeystringYour project authentication key.
options?MossClientOptionsOptional configuration. See Options.

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Returns

MossClient

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create() (eager)

MossClient.create(projectId, projectKey, options?): Promise<MossClient>
Creates a client with eager initialization. The WebAssembly module and embedding model load immediately, before the returned promise resolves.

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Parameters

ParameterTypeDescription
projectIdstringYour project identifier.
projectKeystringYour project authentication key.
options?MossClientOptionsOptional configuration. See Options.

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Returns

Promise<MossClient> Promise that resolves to a ready MossClient.

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Example

// Lazy: WASM/model loads on first API call
const client = new MossClient("your-project-id", "your-project-key");

// Eager: WASM/model loads immediately
const client = await MossClient.create("your-project-id", "your-project-key");

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Options

OptionTypeDescription
model"moss-minilm" | "moss-mediumlm"Embedding model. Defaults to "moss-minilm" (fast, for most use-cases). Use "moss-mediumlm" for higher quality.
baseUrlstringCustom API base URL, for self-hosted Moss instances.
const client = new MossClient("your-project-id", "your-project-key", {
  model: "moss-mediumlm",
  baseUrl: "https://moss.internal.example.com",
});

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Index management

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createIndex()

createIndex(name, docs, options?): Promise
Creates a new index with the provided documents.

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Parameters

ParameterTypeDescription
namestringName of the index to create.
docsDocumentInfo[]Documents to index.
options?CreateIndexOptionsOptional configuration.

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Example

await client.createIndex("knowledge-base", [
  { id: "doc1", text: "Introduction to AI" },
  { id: "doc2", text: "Machine learning basics" },
]);

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createIndexFromFiles()

createIndexFromFiles(name, files, options?): Promise
Creates a new index from files.

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Parameters

ParameterTypeDescription
namestringName of the index to create.
filesFile[]Files to index.
options?CreateIndexOptionsOptional configuration.

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Example

const input = document.querySelector("input[type=file]");
await client.createIndexFromFiles("knowledge-base", Array.from(input.files));

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addDocs()

addDocs(name, docs, options?): Promise
Adds or updates documents in an index.

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Parameters

ParameterTypeDescription
namestringName of the target index.
docsDocumentInfo[]Documents to add or update.
options?MutationOptionsOptional configuration.

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Example

await client.addDocs("knowledge-base", [
  { id: "new-doc", text: "New content to index" },
]);

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deleteDocs()

deleteDocs(name, docIds, options?): Promise
Deletes documents from an index by their IDs.

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Parameters

ParameterTypeDescription
namestringName of the target index.
docIdsstring[]Document IDs to delete.
options?MutationOptionsOptional configuration.

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Example

await client.deleteDocs("knowledge-base", ["doc1", "doc2"]);

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getIndex()

getIndex(name): Promise
Gets metadata about a specific index.

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Parameters

ParameterTypeDescription
namestringName of the index to retrieve.

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Example

const info = await client.getIndex("knowledge-base");

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listIndexes()

listIndexes(): Promise
Lists all available indexes.

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Example

const indexes = await client.listIndexes();

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deleteIndex()

deleteIndex(name): Promise
Deletes an index and all its data.

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Parameters

ParameterTypeDescription
namestringName of the index to delete.

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Example

await client.deleteIndex("old-index");

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getDocs()

getDocs(name, options?): Promise
Retrieves documents from an index.

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Parameters

ParameterTypeDescription
namestringName of the target index.
options?GetDocumentsOptionsOptional configuration for retrieval.

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Example

// Get all documents
const allDocs = await client.getDocs("knowledge-base");

// Get specific documents
const specificDocs = await client.getDocs("knowledge-base", {
  docIds: ["doc1", "doc2"],
});

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getJobStatus()

getJobStatus(jobId): Promise
Gets the current status of an async operation.

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Parameters

ParameterTypeDescription
jobIdstringThe job ID returned by an async operation.

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Example

const status = await client.getJobStatus(jobId);
Queries run against an index that has been loaded into the browser. Always call loadIndex before query.

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loadIndex()

loadIndex(name, options?): Promise
Loads an index into the browser for fast local querying. Call this before query.

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Parameters

ParameterTypeDescription
namestringName of the index to load.
options?LoadIndexOptionsOptional configuration.

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Example

await client.loadIndex("knowledge-base");

// Now queries run locally in the browser
const results = await client.query("knowledge-base", "search text");

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hasIndex()

hasIndex(name): Promise
Checks whether an index is loaded locally in the browser.

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Parameters

ParameterTypeDescription
namestringName of the index to check.

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Example

if (await client.hasIndex("knowledge-base")) {
  const results = await client.query("knowledge-base", "search text");
}

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getIndexInfo()

getIndexInfo(name): Promise
Gets info about a locally loaded index.

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Parameters

ParameterTypeDescription
namestringName of the loaded index.

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Example

const info = await client.getIndexInfo("knowledge-base");

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query()

query(name, queryText, options?): Promise
Performs a semantic similarity search against a loaded index. The index must be loaded with loadIndex first; the search then runs entirely in the browser.

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Parameters

ParameterTypeDescription
namestringName of the target index to search.
queryTextstringThe search query text.
options?QueryOptionsOptional query configuration, such as topK.

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Example

await client.loadIndex("knowledge-base");

const results = await client.query("knowledge-base", "machine learning");
results.docs.forEach((doc) => {
  console.log(`${doc.id}: ${doc.text} (score: ${doc.score})`);
});

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refreshIndex()

refreshIndex(name): Promise
Refreshes a loaded index from the server, picking up the latest changes.

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Parameters

ParameterTypeDescription
namestringName of the loaded index to refresh.

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Example

await client.refreshIndex("knowledge-base");

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unloadIndex()

unloadIndex(name): Promise
Unloads an index from the browser, freeing its resources. Querying it again requires calling loadIndex first.

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Parameters

ParameterTypeDescription
namestringName of the index to unload.

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Example

await client.unloadIndex("knowledge-base");

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Cleanup

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dispose()

dispose(): void
Releases all resources held by the client, including loaded indexes and the WebAssembly runtime. Call this when the client is no longer needed.

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Example

client.dispose();